The present invention relates to a method of forming a transfer member in an image forming system. More particularly, this invention relates to a method of manufacturing seamless multilayered transfuse belts for use in the imaging forming system.
In a standard image forming process, a charged latent image is generated by directing an array of charged particles from a print cartridge towards an imaging member. Toner is attracted to the charged latent image on the surface of the imaging member to form a toned image. After the toned image is developed on the imaging member, it is transferred, either directly to paper or to another type of print substrate, or indirectly with a transfer member. To permanently fuse toner onto a print substrate, it is usually necessary to elevate the temperature of the toner to a point at which the constituents of the toner coalesce and become sticky. This heating causes the toner to flow into the fibers of the print substrate. Thereafter, as the toner cools, solidification of the toner causes it to firmly bond to the print substrate. After transfer and fusion of the final image, the residual toner is cleaned from the imaging member (and the transfer member if used).
An example of a prior method of manufacturing a transfer member, such as a seamless belt, for an image forming system is disclosed in U.S. Pat. No. 5,409,557, the contents of which are incorporated herein by reference. In this method, the seamless belt is formed by spraying a coating solution onto a reinforcing member. A thin uniform layer is built up on the reinforcing member by repeated spray passes. After the desired thickness is obtained, the belt is dried, and released from the reinforcing member upon cooling to room temperature.
Other conventional seamless transfer belts are fabricated using compression-type molding. This manufacturing process involves casting rubber onto a mold, applying a heat-shrink wrap, and curing the belt in an autoclave.
There are significant disadvantages to these types of transfer member manufacturing techniques. Using a spray-coating process or a compression molding process, it is difficult to produce a belt having-a-precise and uniform thickness. Before the belt can be used in an image forming system, it is necessary to grind both the spray-coated and the compression molded belt to have the necessary thickness uniformity. This requires precise, complex and expensive post finishing operations to be performed on the belt. Without these operations, the image quality is compromised.
The present invention provides an improved method of manufacturing seamless belts for an image forming system. This method produces a seamless multi-layered belt having a precise and uniform thickness.
According to one aspect of the invention, the belt is formed by dispensing liquid polymer onto an internal surface of a rotating mold and curing the liquid polymer in situ while the mold still rotates. The present invention includes alternate methods of forming the belt using a liquid polymer in a rotating mold. In one embodiment, the belt is formed by applying a conductive layer to the rotating mold, followed by a liquid polymer layer and a fabric backing. In an alternate embodiment, the belt is formed through a reverse method, and then inverted.
Both embodiments provide a simplified method of manufacture while producing a superior end product. This invention constructs seamless belts that are usable when they are cast, without the need for post-finishing operations to achieve the essential thickness requirements.
In one embodiment of the invention, a transfer member suitable for use in an image forming system is manufactured by applying liquid polymer to a rotating mold and curing the liquid polymer.
According to an alternate embodiment, a transfer member is formed by dispensing a conductive coating to an internal surface of a rotating mold, followed by an application of a first liquid polymer coating to the mold. The conductive coating and the first liquid polymer coating are cured to an intermediate stage. A second liquid polymer coating is applied to the cured liquid polymer, followed by application of a support material to form a stacked structure. A heavy elastomeric liner, which either does not bond to the liquid polymer or has a release agent on its surface, is inserted into the mold and the stacked structure is cured to a final stage while the mold is rotating. The elastomeric liner and the stacked structure (the transfer member) are removed from the mold.
In yet another embodiment, a transfer member is formed by first dispensing a thin coating of liquid polymer to an internal surface of a rotating mold, followed by application of a support material. A heavy elastomeric liner, which does not adhere to the curing rubber, is optionally inserted in the mold. The liquid polymer and the support material are cured to an intermediate stage while the mold rotates. A second liquid polymer coating is applied to the rotating mold, and a conductive coating is applied to the second liquid polymer coating to form a stacked structure. The stacked structure is cured to a final stage, removed from the mold and inverted.